Synthesis of Models of the Bc Ring Systems of Mpc1001 and Mpc1001f

Piperazinedione 13, representing the BC rings of the anti-prostate cancer fungal metabolite MPC1001, was prepared by a route in which a sulfur-stabilized carbanion derived from 22 cyclizes onto the terminal ester of the pendant chain attached to N(1). Another model, 14, was synthesized by cyclization of an α-ketoamide nitrogen onto an ester; 14 represents the BC rings of MPC1001F.